How to delete read only files.

[Balaji Palaniswami]

Hi,

I am trying to delete read only files.

# pwd
/usr/home/bp/nfsroot/lib
# whoami
root
# ls
libc.so.7       libcrypt.so.5   libthr.so.3
# ls -ltr
total 3264
-r--r--r--  1 root  wheel  1460592 Jan 29 12:07 libc.so.7
-r--r--r--  1 root  wheel    51640 Jan 29 12:07 libcrypt.so.5
-r--r--r--  1 root  wheel   109568 Jan 29 12:08 libthr.so.3
# rm -rf libc.so.7
rm: libc.so.7: Operation not permitted

# chmod 777 libc.so.7
chmod: libc.so.7: Operation not permitted

Please suggest me some ways to delete these files.

Thanks,
Balaji